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Hong Kong
Stage 1

Add 3 numbers (mix of single or two digit numbers)

Lesson

Adding 3 numbers at a time might look tricky, but you can use the same strategies used for adding 2 numbers to help you.

Have a look at the video below.  Watch how the strategies of using a number line and compensation were applied.

One strategy was not mentioned - bridge to 10.  You can also apply bridge to 10 with 3 numbers.  What do you think that might look like?  

Worked Examples

question 1

Evaluate $41+7+1$41+7+1

question 2

Evaluate $3+42+4$3+42+4

Question 3

A bakery sells $105$105 cakes, $60$60 bread rolls and $50$50 muffins in the morning.

What is the total number of items the bakery sells in the morning?

  1. $155$155

    A

    $110$110

    B

    $215$215

    C

    $205$205

    D

 

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